The present invention relates to a golf ball and, more particularly, a golf ball core or cover component that includes glass ionomers, ormocers, or other hybrid organic/inorganic compositions.
Golf balls can generally be divided into two classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by tensioned elastomeric material, and a cover. Solid balls have traditionally been considered longer and more durable than wound balls, but also lack the particular xe2x80x9cfeelxe2x80x9d that is provided by the wound construction and typically preferred by accomplished golfers.
By altering ball construction and composition, however, manufacturers can vary a wide range of playing characteristics, such as resilience, durability, spin, and xe2x80x9cfeel,xe2x80x9d each of which can be optimized for various playing abilities, allowing solid golf balls to provide feel characteristics more like their wound predecessors. The golf ball components, in particular, that many manufacturers continually look to improve are the center or core, intermediate layers, if present, and covers.
The core is the xe2x80x9cenginexe2x80x9d of the golf ball when hit with a club head. Generally, golf ball cores and/or centers are constructed with a polybutadiene-based polymer composition. Compositions of this type are constantly being altered in an effort to provide a targeted or desired coefficient of restitution (xe2x80x9cCORxe2x80x9d) while at the same time resulting in a lower compression which, in turn, can lower the golf ball spin rate, provide better xe2x80x9cfeel,xe2x80x9d or both. This is a difficult task, however, given the physical limitations of currently-available polymers. As such, there remains a need for novel and improved golf ball core compositions.
Manufacturers also address the properties and construction of golf ball intermediate and cover layers. These layers have conventionally been formed of ionomer materials and ionomer blends of varying hardness and flexural moduli. This hardness range is still limited and even the softest blends suffer from a xe2x80x9cplasticxe2x80x9d feel according to some golfers. Recently, however, polyurethane-based materials have been employed in golf ball layers and, in particular, outer cover layers, due to their softer xe2x80x9cfeelxe2x80x9d characteristics without loss in resiliency and/or durability.
There remains a need, however, for improved golf ball center, core, layer, cover, and coating materials and/or blends having further reduced or modified hardness and modulus while maintaining acceptable resilience and superior abrasion resistance and feel. The present invention is directed to golf balls having components formed of novel hybrid materials, such as glass ionomers, ormocers, and other inorganic-organic materials. Ormocers, for example, are a relatively new class of composite materials formed of ceramic and polymer networks that combine and interpenetrate with one another. Ormocers may be generally classified as one, either organic- or inorganic-doped systems typically based on one major phase containing a second one in a relatively low amount; and two, either organic- or inorganic-doped systems in which the fraction of each component in the system is of the same order of magnitude. These and other novel hybrid materials described herein are investigated for use in a variety of golf ball components that include, but are not limited to, golf ball centers, cores, layers, covers, and coating materials and/or blends, continuous or non-continuous layers, thick of thin films, fillers, fibers, flakes, windings, adhesives, coupling agents, compatibilizers, composites, reinforcements, and inks.
The present invention is directed to a golf ball comprising a core and a cover layer, wherein at least one of the core or cover layer comprises a hybrid material. The hybrid materials may include glass ionomers, resin-modified glass ionomers, ormocers, inorganic-organic materials, silicon ionomers, dental cements or restorative compositions, polymerizable cements, ionomer cements, metal-oxide polymer composites, ionomer cements, aluminofluorosilicate glasses, fluoroaluminosilicate glass powders, polyalkenoate cements, flexible composites, and blends thereof.
The fluoroaluminosilicate glass powders have a specific gravity of 2.4 to about 4.0, a mean particle size of 0.02 to about 4 xcexcm, and a BET specific surface area of 2.5 about 6.0 m2/g. The hybrid material can include a polymerizable composition comprising a polymerizable resin composition and a filler composition comprising a bound, nanostructured colloidal silica. The hybrid material may also include a diluent acrylate or methacrylate monomer in an amount sufficient to either increase the surface wettability or decrease the viscosity of the composition.
If used as the hybrid material, the diluent monomers include hydroxy alkyl methacrylates; 2-hydroxyethyl methacrylate; 2-hydroxypropyl methacrylate; ethylene glycol methacrylates; ethylene glycol methacrylate; diethylene glycol methacrylate; tri(ethylene glycol) dimethacrylate; tetra(ethylene glycol) dimethacrylate; diol dimethacrylates; butanedimethacrylate; dodecanedimethacryalte; 1,6-hexanedioldimethacrylate; and mixtures thereof. There may also be a blend of the hybrid materials and polyolefinic ionomers.
The hybrid materials may include flexible composites comprising about 2 to 15 weight percent of a flexible monomer portion comprising one or more flexible co-monomers of the general formula R1xe2x80x94Oxe2x80x94[(CHxe2x80x94R2)nxe2x80x94Oxe2x80x94]zxe2x80x94R3, wherein R1 and R3 are acrylate or methacrylate functional groups; R2 is selected from the group of hydrogen, methyl and ethyl; n is from 3 to 5 and z is from about 3 to about 20; and the monomers have average molecular weights from at least about 300 or higher; about 30 to about 80 weight percent of a filler portion; about 18 to 60 weight percent of a comonomer portion comprising one or more co-monomers capable of polymerizing with the flexible monomer portion; and a polymerization catalyst system for polymerizing and hardening the composition. Additionally, the hybrid materials may include a powder component containing aluminosilicate and a liquid portion. The liquid portion may be polyacrylic acid, polymaleic acid, polyitaconic acid, carboxylate polymers, carboxylic acid polymeric structures, acrylic acid, maleic acid, crotonic acid, isocrotonic acid, methacrylic acid, sorbic acid, cinnamic acid, fumaric acids, and mixtures thereof.
The hybrid materials may also include a reaction product of an aluminosilicate glass powder containing at least one element selected from the group consisting of Ca, Sr, and Ra, and an organic acid containing one or more carboxyl groups in one molecule thereof; a methanol-insoluble polymer; a monomer containing at least one unsaturated double bond and having no acidic group; a polymerization initiator; and, optionally, a filler. Further, the ionomer cement includes an ion-leachable glass, calcium aluminosilicate glass, or borate glasses.
The hybrid material further can also be formed of a chelating agent in an amount sufficient to modify the rate of cure. Preferably, the hybrid material is an ormocer formed by the hydrolytic condensation of one or more silicon compounds, and the subsequent polymerization of organic monomers, wherein at least one silicon compound comprises vinyl ether radicals of the formula: 
wherein R represents hydrogen, methyl, or ethyl. Further, the hybrid material includes an interwoven organic-inorganic solid composite.
The ball may be of any construction, however in one embodiment the core comprises a center and an outer core layer. Preferably, at least one of the center or the core layer comprises the hybrid material. In another embodiment, the cover comprises an inner cover layer and an outer cover layer. Preferably, at least one of the inner or outer cover layers comprises the hybrid material. Ideally, at least one of the inner or outer cover layer has a thickness of less than about 0.05 inches and/or the core has an outer diameter of at least about 1.55 inches. Preferably, the core has an outer diameter of between about 1.57 inches and about 1.62 inches. The hybrid material be formed into thick or thin films, fillers, fibers, flakes, particulates, windings, adhesives, coupling agents, compatibilizers, composites, short or long fibrous reinforcements, and inks.